The present invention relates to a parallel plate structure provided with a PZT lead (Pb) Zirconate Titanate) thin-film bimorph and method of fabrication thereof, and more particularly, to structures used as piezoelectric actuators.
A bimorph, which is known in the prior art, includes a plate-like substrate, two PZT devices (lead zirconate titanate: ceramics containing a solid solution of lead titanate and lead zirconate), which are formed on the front and rear surfaces of the substrate and which function as piezoelectric devices, and electrodes formed on each PZT device. Voltage is applied to both of the PZT devices so that one of the PZT devices expands while the other contracts. Since this deforms the bimorph entirely in a certain direction, the bimorph is used as an actuator.
However, when employing preformed PZT devices, it is difficult to make the devices thinner in subsequent processes. Accordingly, the production of a more compact bimorph is difficult. Furthermore, alot of time is requiring to adhere the PZT devices to the front and rear surfaces the substrate. This lengthens the fabrication time of the bimorph.
Additionally, since the bimorph is formed as a monolithic single plate, the bimorph is apt to deform in an undesirable direction. This results in a shortcoming in which the bimorph twists and does not deform accurately.